Electrical remote transmission system for transmitting varying magnitudes



Dec. 1.4, 1954 ANDERSSQN 2,697,190

ELECTRICAL REMOTE TRANSMISSION SYSTEM FOR TRANSMITTING VARYINGMAGNITUDES Filfld Jan. 26, 1951 4 Sheets-Sheet. l

5 \ga k 4 '6 xs V g s x. I 35 ZSrwentor attorney 14, 1954 K. N.ANDERSSON 2,697,190

ELECTRICAL REMOTE TRANSMISSION SYSTEM v FOR musummc VARYING HAGNI-TUDESFiled Jan. 26, 1951 4 Sheets-Sheet 2 3 :1 men tor KWRL MM flNDf/YSS cwattorney ANDERSSON REMOTE TRANSMISSION SYSTEM ING VARYING MAGNITUDES 4Sheets-Sheet 3 Inventor attornog K. N. AL

ELECTRIC Dec. 14, 1954 FOR TRANSMITT Filed Jan. 26, 1951 K. N. ANDERSSONAL REMOTE TRANSMISSION SYSTEM ING VARYING MAGNITUDES Dec. 14, 1954 4Sheets-Sheet 4 ELECTRIC FOR TRANSMITT Filed Jan. 26, 1951 3nventor Ki;U-

M294 finwmssow general type, above referred to, cration and moreaccurate than the systems as hitherto United States Patent Ofiiice2,697,190 Patented Dec. 14, 1954 ELECTRICAL REMOTE TRANSMISSION SYSTEMFOR TRANSMITTING VARYING MAGNITUDES Karl Nial Andersson, Grondal,Sweden, assignor to Aktiegolaget Bofors, Bofors, Sweden, a corporationof weden Application January 26, 1951, Serial No. 207,971 Claimspriority, application Sweden January 27, 1950 7 Claims. (Cl. 318.28)

The present invention relates to remote transmission systems fortransmitting varying measured values or remote firearm control.

Accordingly, one of the objects tion is to provide a remote transmlssionsystem of the which is reliable in opknown.

A more specific object of the invention is to provide a system whichafiords an accuracy suflicient for firearm control stations.

Other and further objects, features and advantages of the invention willbe pointed out hereinafter and set orth in the appended claims formingpart of the application.

In the accompanying drawing several now preferred embodiments of theinvention are shown by way of illustration and not by way of limitation.

In the drawing:

Fig. 1 is a typical circuit diagram of the receiver of a able forsine-shaped signals.

Fig. 3 is a circuit diagram of a phase detecting means part of thecircuit system according to Fig. 1

ig. of the phase detecting means according to Figs 2 and F' is a typicalcircuit system of a remote trans- .sutlices to. state that 2 elements 3and 6. It will be apparent that when phase etector 2 receives a signal 0a certain kind, the unit 3 signals identiby phase detector 2. The conthephase detector is connected with the oscillator 4 via reactance valvemeans 5 for the control of the oscillator. Reactance valve 5 serves asradio receiver. plied e two signals are supplied to the stator Windingof a rotary phase shifter his winding is arranged in such a way that arotatwinding of the phase shifter 11 is connected to a unit 10, which isconnected in parallel with a switch 15. Unit 10 position lhe controlslgnal terminal of connected to a motor 13 via an amplifier 12. 14 ofthe motor 13 is connected with the rotor of the phase shifter 11. Motor13, when rotating, turns the rotor of the said phase shifter. The phasedetector 9 is fed with a value of measurement signal over the terminal8.

The device, as hereinbefore described, operates as follows:

The reference signal supplied to the phase detector 2 compared in thedetector with the signal coming from the oscillator 4. The way that itgenerates a two first-mentioned signals differ from relation.

proportional to the measured value or magnitude which is to betransmitted.

In order to ascertain this in the osci lator 4 nd synchronized wi hpredetermined after being amplified, causes rotation of v, the referencenumbers 16, 17, 22, 23, 28 and ZQIIIQiCa fG terminals; that the'numbers24 and 25 'indicate 'capacitors; that the numbers 26 and 27 indicateresistors; that the numbers 18 and 19 indicate transform- Hand 9' ers;and that the numbers and 21 indicate rectifier and the refertubes. Thevalue of measurement signal ence signal are supplied to.the terminals16, 17 and 22, circuit diagram 23, respectively. Fig. 3 shows a typicalof a phase detector which is particularly adapted for square-formedvalues of measurement signals and the reference si nal. in this figurenumerals 30, 31, 38, 39, 45 and 46 indicate terminals; numerals 32 and33 indicate transformers; numerals 34 and 37, 41 and 44 indicateresistors; numerals indicates an auxiliary voltage source; numerals 35and 36 indicate triode tubes: and numerals 42 and 43 indicatecapacitors. In this circuit diagram, the reference signal and the valueof measurement signal are 1supplied to the terminals 30, 31 and 38, 39,respective y.

The nature of the control s gnal which is obtained as an output signalat the terminals 28, 29and 45, 46 respectively, and at different phaserelati ns between the v lue of easurement signal and the referencesignal, is illustrated by means of the graph 47 of the Fig. 4 In thesaid figure. the ordinate shows the voltage f the control signal and theabscissa shows the phase shift between the two first-mentioned signals.The graph indicates that the voltage of the control signal is zero for aphase shift of Sir/2 radi ns and that the voltage is positive for aphase shift which is somewhat less than 51r/ 2 radians and that thevoltage is negative for a phase shift a little greater than 51r/2radians. The graph will also obt in the s me characteristics at thepoint 1r/ 2. It has proved conven ent to let the detector work aroundthe point 1r/2 radians. The control signal will always rotate the motor13 in such a way that the oscillator signal will be 1r/2 radians, phaseshifted in relation to the value of measurement signal. The indi tor ofthe hase shif er 11. which indicates the phase difference between thereference si nal and the value of measurement si nal sh d be calibr tedwith regard to the said constant phase shift 1r/ 2 radians.

In Fig. 5. a re te trans ission ystem is shown, serves to transmit twovalues of measurements. The reference signal and the value ofmeasurement signals ma be either sinehaped or square-sha ed.

The elements of the receiver part. which are identical with those of theFig. 1 have been given either the same reference numbers or the samereference numbers with prime signs.

The system com rises. in the transmitter, a low-frequency generator 48.which su plies a low-frequency signal to the three modulators 52, 57 and62. The said modulators are also fed with carrier frequency si n ls ofdifferent fre uen s from the high-frequency oscillators 53, 58 and 63The low-frequency signal modulates the carrier-frequency signals in themodulators. The modulated carrier-frequency signals are sent by wire orwireless to the receiver part. The oscillator 48 is connected to themodulator 52 via an amplitude limited 50, which can be a switch 51, tothe modulator 57 via a phase shifter 54 and an amplitude limiter 55,which can be short-circuited by a switch 56 and to the modulator 62 v aa phase shif er 59 nd an am litude limiter 60, which can be shortcircuited by a switch 61.

When it is desired to work ith sine-shaped signals, all three switchesare closed. The switches are opened when square-shaped signals aredesired.

The values of me surements which are to be transmitted are set on thephase shifters 54 and 59. The modulated signal from the modulator 52.which constitu es the reference signal, is fed to the receiver togetherwith the signals from the m dulat rs 57 and 62. to hree b nd passfilters 64. 66 and 68. The filter 64 lets the signal from the modulator52 pass. the filter 66 modul tor 57. and the filt r 68 the signal fromthe modulator 62. Each of the said band-pass filters is connec ed to adetector 65, 67, and 69, res ectively. which each take out alow-frequency signal. The two first-menti ned detectors are connected tothe phase detectors 2 and 9. The two detectors are an integral part of asystem identical to that of the Fig. l The detector 69 is connected to aphase detector 9' which is an integral part of an element group 9 to15'. The said group is identical with the group 9 to the case of thegroup 9 to 15, connected to the amplifier.

In regard to the design and function of elements 9 to to the system ofthe Fig. 1.

Fig. 6 shows a remote transm1s on system for three whi h the signal fromhe 15. The first-mentioned group is also, as in a 15' reference is madeto the description of values of measurements where the transmittedsignal are pulse signals.

The elements which are identical with elements of Fig. 1 have either thesame reference numbers or the same reference numbers with prime anddouble prime signs.

In the transmitter of the system, an oscillator 70 is coupled to thepulse generators 71 to 75. Generators 71, 72 are directly connected withthe oscillators 70 and the other generators via the phase shifters76--78. Phase shifters 76, 77, 78 operate in the same manner as in thepreviously explained system. In all pulse generators, a pulse isgenerated at the Zero point at the beginning and at the end of eachperiod of a signal. The units 79 to 82 form transmitting means that caneither be closed or opened for signals and are connected to the pulsegenerators 72 to 75. The pulse generator 71 is connected to all thesynchronous switch units 79 to 82 of the transmitter and controls theseunits in such a way that during eac period, one of the units 79 to 82 isopen during the whole of the period while the others are closed.Furthermore, the unit which shall be open during the following perio isprepared therefor. The units are moreover arrange so that they areopened successively in the order in which they are mentioned, and thatwhen all have been opened, the first unit is opened anew and then thesecond, and so on. The pulses of the pulse generator 72 are speciallymarked and used as reference pulses. The pulses from the transmitter aresupplied either by wire or wireless to the synchronous switch units 84to 87 of the receiver. Th receiver units are of the same kind as thetransmitter units 79 to 82. The units 84 and 85 are connected to thephase detectors 2 and 9, which are integral parts of a system which isidentical with the one shown in the Fig. l. The units 86 and 87 areconnected to the groups of elements to 14 and 9" to 14", respectively.The said two groups are each identical to the element group 9 to 14 andconnected to the amplifier 7. The units 84 to 87 are controlled by apulse generator 83 which is connected to the oscillator 4 in the samemanner as the units 79 to 82 to the generator 71 but so that the unitsopen at the same time.

It is believed that the operation of the system of Fig. 6 will now beunderstood if examined in conjunction with the previous description.

respect to certain now preferred examples and embodiments of theinvention it will be understood by those skilled in the art afterunderstanding the invention, that various changes and modifications maybe made without departing from the spirit and scope of the invention andit is intended, therefore, to cover all such changes and modificationsin the appended claims.

What is claimed as new and Letters Patent is:

1. In a remote transmission system for transmitting varying measuredmagnitudes from a transmitter to a receiver by signals havmg arepeatingwave pattern and of different phase posi 'ons relative to areference signal having a repeating wave pattern, each of said differentphase positions corresponding to a measured magnitude, a receivercomprising oscillating means, phase shifting, means connected to theoscillating means, first signal comparing means connected to the phaseshifting means, said comparing means being arranged to compare desiredto be secured by a signal generated in the oscillating means an fed tothe comparing means via the phase shifting means with a signalrepresenting one of said measured magnitudes and to produce an errorsignal in response to a difference between the phase relation of the twosignals and a predetermined phase relation, motor means coupled withsaid phase shifting means for control of the latter by a rotation of themotor means, circuit means for feeding said error signal to the motormeans for actuating the latter so as to adjust the phase shifting meanscorresponding to said error signal for restoring the phase relation ofthe said two signals relative to said predetermined phase relation,second signal comparing means, circuit means for feeding said referencesignal and the signal generated by the oscillating means to the secondcomparing means, the said latter means comparing the phase relation ofthe said reference signal and the signal generated by the oscillatingmeans and producing a second error signal in response to a differencebetween the said phase relation and a predetermined phase relation, andcircuit means feeding the second error signal to the oscillating meansso as to restore the phase relatron of the two last mentioned signalsrelative to said predetermined phase relation.

s ort duration relative to the periodicity of the wave remotetransmission system as defined in claim 1, wherein the said signalsrepresenting a measured magmtude and the reference signal aresquare-shaped.

7. A remote transmission system 6, in combination with amplitudelimiting means included References Cited in the file of this patentNumber UNITED STATES PATENTS Name Date Riggs July 21, I936 Seeley Dec.19, l939 Isbister et al. Sept. 23, 194] Moseley et al. Sept. 23, 1941Bond Dec. 23, 1947 Manley Nov. 14, 1950 Schmitt et al. June 12, 1951Triman June 19, 1951 Marrison Aug. 14, 1951 McCallum Mar. 11, 1952

